Facile approach to prepare HSA-templated MnO nanosheets as oxidase mimic for colorimetric detection of glutathione.

In this work, a simple, rapid, and highly sensitive colorimetric assay for the determination of glutathione (GSH) was developed. It employs human serum albumin (HSA)-templated MnO nanosheets as an artificial oxidase. HSA-templated MnO nanosheets can oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to a blue oxTMB product with a significant increase in absorbance at 652 nm in the absence of HO. When GSH is introduced, the MnO nanosheets are reduced to Mn ions, thereby inhibiting the formation of oxTMB. Based on these findings, a simple colorimetric assay was developed for the detection GSH in the range of 10 nM to 5 μM with a low detection limit of 5.6 nM. Importantly, the proposed method was successfully used for quantitative determination of GSH in biological fluids, such as human serum samples.